libmix: fix a VC1 parser issue

BZ: 129080

Two issues have been fixed in VC1 parser.
1. User data should be identified.
2. slice_vertical_position should be parsed from bitstream
   instead of being assigned slice number.

Change-Id: Idaa5d40aa473b9f9771b0eb308c13d0553ddf2f9
Signed-off-by: Tianmi Chen <tianmi.chen@intel.com>
Reviewed-on: http://android.intel.com:8080/133550
Reviewed-by: Shi, PingX <pingx.shi@intel.com>
Tested-by: Shi, PingX <pingx.shi@intel.com>
Reviewed-by: cactus <cactus@intel.com>
Tested-by: cactus <cactus@intel.com>
1 file changed